Team Gas Diary's

Hey guys
Thought I would post a some what build report / blog on my builds. Decided to go back into this weird hobby as frankly I missed it heeps. Since my last involvement with robots I have mostly been building arcade cabinets and a handheld netbook mame emulator
Things have changed and I now live in a studio apartment in Wimbledon, London. I have a balcony but next to no space. So lacking my larger tools and room to make a mess.
So my diary could be helpful for those in similar positions.


My mentality on robot projects is also going to change. Rather than 'try and build for this event' I am going to take my time. It will be ready when its ready. My past robots have really suffered from rushing and not proper planning.

I designed the robot in maya which isn't recommended. Its what I use on a day to day basis and didn't want to learn new software. I wanted the robot to have quite a lot of parts to snap together. Advantages is if a part gets damaged I can just print a new piece and cut it out.

Main chassis is 6mm nylon, backed up with 8mm HDPE and the armor is undecided but Ti or ali is being considered mostly on weight
47 different robot parts of Nylon
42 pieces of HDPE
After I was happy with the design I imported it into illustrator and printed it all out. Initially I tried to print a giant tiled a4 sheets to create 50 by 100cm. After trying to attach the 7th sheet and not happy with the accuracy I had more sense and printed out as many parts that i could fit on a4 sheets and layed them out accordingly. Only the bulkheads needed more then a4 and was an easy task of lining up the prints.

Cutting wise There were a few tools which were essential
router for the long straight lines and the bevels on the bulkheads. FIrst time using this and made sure I had lots of practice before working on the nylon. Used G clamps, very large spirit level ruler and took my time
Rage mitre saw which is more accurate and used as much as possible and can cut up to 220 mm
Jigsaw which was for the more unacurate cuts but was used occasionally on the small parts
Dremel Surprisingly very efficient toll in helping the chassis slot in together
Piller drill for the holes

The nylon was tricky to cut at times. It got caught on the mitire saw occasional and I had to do very slow cutting on it. Melted a lot when cut with a jigsaw.
HDPE is awesome to work with. Very soft, like butter in most tools. Was perfect for bridging parts of the chassis together.

Assembly was straight forward. Surprisingly time consuming. but most is being held by m3 bolts and 3mm screws. Robot looks very ikea. So many parts. Surprisingly everything is very accurate. Really impressed with my handy work. Measurements are only off by 1mm here and there but still very much in range of my CADAttachment 3776Attachment 3777Attachment 3778Attachment 3779Attachment 3780Attachment 3781

Very nicely done, looking brilliant :)

Sorry, I didn't mean to thank your post, my iPods touch screen is a bit glitchy!

You robot is looking excellent though :)!

Thanks Guys! I was a bit baffeled about the like Sam as I didnt do anything ^_^
Really trying to do my best with this build. As little bodging as possible

Lazy day at work and I found a video of Trojan II
http://www.youtube.com/watch?v=2fdnOtNWfPg
Be warned, Dave is very rude at the end :P

How did you cut everything so straight and square?!

When I tried to cut my HDPE bulkheads by hand they were about as square and a curly wurly!

Howdy PJ
The bulkheads are Nylon and I cut them with a router and a large spirit level ruler (picture related)
Attachment 3782
Placed the ruler about 5cm away from the cut (way my router is setup)
Secured very tightly with heavy duty G clamps (bit of scrap wood to not damage the ruler and the bench)
Push firm and cut with the router.

Happy with the results but as expect few MM off here and there without CNC cutting. So I bolted the bulkheads together and filed them down till they were all quite identicle
Hope that helps

#edit
Sorry you quite clearly said everything rather then just the bulkheads
Big thanks to loads of the straight cuts to my sliding mitre saw. Made life a lot easier and it has a large slide function. But as I said nylon is very scary to cut on it. Have to cut very slowly or it catches rather then cuts.

Good idea, I tried something similar with a Jigsaw, but didn't work out, Router might work better! Cheers!

Good to see you back in the game Marco :)

Apologies for that video :)

Cheers Dave and haven't quite entered the game :)
Been terrible and have parts for 2 ants and probably 2 feathers

Wow are they LEM's / Etek's in a feather!! Or scooter motors etc?

300 watt scooter motors which are planned to be overvolted and run by a wotty
Yep silly, I know.
Upgrade goals are to bring the voltage from 24 to close to 30 with liths and replace the wotty with a sidewinder for space
I did try to run it on an scorpion XXL but it blew before it even reached the arena.
This version will also be much quicker at over 15mph

Sadly as I expected I havnt been able to spend much time in the past couple of days working on Trojan but I have made a few important decisions.

For the drive in Trojan 2 I had about 3.5 gear reduction with one sprocket system going from the motor to the two wheels.

To make things more reliable I have decided to go for two separate systems. First reduction through spur gears to the front wheels then 6mm chain and sprockets to the rear wheels.
Already done some work towards this by constructing one of the wheels and nearly hacksawed all the sprockets. Lots of arm work needed!

After watching some past videos I realise that having the biggest motors in the world wont mean jack if you dont have grip to take advantage of the torque. I have more grip but I still will be wheel spinning constantly. So I decided to get more speed and changed the reduction from 3.5 to 2.
This will make the robots max speed of 20mph! But should still have the torque to push other robots quite easily. Should be entertaining!
So just ordered some sprockets and now doing 2 chain systems. If things are a bit crazy I can just go to the
sprockets and the 3.5 reduction.

Attachment 3788
Also thinking about the lifting prongs at the front and it might be tricky. But I think a worm gear reduction from a drill motor will have good results. Needs to be an afterthought as I need to work out what weight i have.


Also had a quick sketch up in 3d of the next feather. Bit more impressive looking but probably won't be as good.
Attachment 3789Attachment 3790
This weekend will be set on finishing the chassis and all the tiny little plates that attach around the wheels.

Wow I might even look good to possibly make Guildford but personal promises need to hold up. I am not going to rush.


Few questions
Is 6mm chain fine? I used to have ⅜ and that was far too big

Suitable featherweight armour nowadays. Ali, ti or steel. Would 2mm steel be a deathwish on the front plate? I had 3mm ali plate on the top for a long while and seemed fine against little hitter. Last time I fought a featherweight spinner was back in 2003 so my experience with them is limited :)
Lastly how do I set my avatar to appear in my posts? :)

Go top right - settings
Left bottom side - My profile
Edit Avatar

Your profile picture and avatar are 2 different things. The avatar is the one that appears on the forum itself next to your posts.

For image re-sizing I use this. Quick and easy:
http://www.shrinkpictures.com/

You're a star. Cheers bud

You're welcome.

As for the robot stuff, people love plastics are armour at the moment. HDPE weighs 1/8th that of steel, so a combination of the potential thickness you can use and it's great impact resistance (plus the fact that at that width it can also be strutural) means it's very popular.
Ti is great, light and strong but expensive. And then people use wear resistant steels like Hardox for spinner proof armour, but hard to find and heavy.

As for drive transfer I believe lots of people use those chains, but nowadays people are edging towards timing pulleys and belts. They're lighter, don't stretch and don't come off. You can also get HDT belts if you're worried about them breaking.

That grabbing robot looks awesome!

Looking forward to this build! Will be crazy if this thing still has the grunt at just 2:1.

2mm steel definitely is a deathwish. Pretty much 2mm of anything is a deathwish, save maybe high grade ti. We had I think 4mm steel on the front of our machine for the champs, and after just two fights with the spinner that came 6th (Inertia XL) it was literally like a piece of lettuce. Useless. You're more or less limited to Hardox, titanium or very thick plastic (HDPE works well) these days.

We also happened to use 6mm chain for our weapon and I'd say don't bother, if you can avoid it. It will work, but it stretches an alarming amount (you'll most likely need more than one tensioner), and getting it on and off is a huge pita, we found. We are going to move to "HTD" timing belts. I have good word that 9mm wide HTD5 belts work very very well for drive and spinning weapon transmission. Here's one source of many in the UK: http://www.beltingonline.com/5mm-htd-timing-belts-4575 - payoff in being lighter with the aluminium pulleys, too.

Keep us posted. :)

In the last version I did used to have 8mm HDPE but the front scoop used to get so scuffed I would almost have to replace it after each event. I dont really need it for support any more as the chassie is quiet strong.
Hardox is of course awesome but isnt the thinest you can get it at 3.2mm still? And thinner its too brittle (something along those lines)
Steel or ti on the front scoop I think is my main options. But im not sure if 2mm steel is too thin
Quite heavy as well at about 1kg just for the front plate
.5 kg 2mm ti - Might look into that

Timming belts are nice. I did get these parts a few years ago and belts where only really availble from specific suppliers and where rather expensive. Now I see them on technobots. Another thing to possible replace for the weaponised version if the chains are unstable.

Thanks for the kind words on the feather. Been wanting to build a heavy like that for years. Infact this is the topic from 2008 (oh my)
Attachment 3792Carnifex Heavy
In the thread there is a video of the mech in action (electric)
Really wish I could make the heavy. Maybe next year. Have prity much everything to do it.

A while ago I designed a similar weapon! That design looks awesome. I love this sort of mechanism. I came up with essentially the same, just switched around for faster lift...

http://oi40.tinypic.com/a5gah5.jpg

I designed that before this year's champs, I definitely would not build it in that design now, having gained more experience.

Ahh Ellis, chucking a real spanner in my works :)
Thanks for the advice. I am used to chains gaining some slack and there is plenty of opportunity options to adjust tensioners if its tolerable. If I am having zero luck then I will change it around and get some belts. I dont think they will be taking as much punishment as weapon chains. I am covering the wheels as much as possible to avoid stress.
Armour is causing me more of a headache than anticipated. Dam featherweight spinners looking really dam decent. Think 3.2 hardox or 2mm good grade TI. It will be really well braced because of the chassis and it not being just a standalone part.

Also really mixed on 3.5:1 or 2:1. I have the option to switch between them at least. Torque on these motors is very impressive. About half of a 750. Going to have a play.

Cant wait for the weekend to build me robots.

I think 3.5:1 is worth it. 15mph is still bloody quick, and you're very unlikely to be able to use more speed in the 5x4m RoboChallenge arena. Our machine does 10mph and it feels pretty quick! When you're pushing a machine you'll probably benefit from having more grunt, and if they're even slightly on top of you you regain grip with their weight so the torque is used.

Magnets might be an option if you want to put the power of those motors to proper use?

I don't think 4mm steel is as bad as Ellis says so, the chassis of satanix is 4mm steel and the wedges have survived whacks from all sorts. I think it's to do with the way it's constructed, with the wedge plates braced in between the side plates. It has been pierced before, but did not bend like Ellis's plate.

This is true and should have occurred to me. When 4mm steel forms a tight structure it is still very much usable, just as a freestanding front plate it may not last long. Today's verticals can catch even the lowest of wedges.

Welded plate underneath the wedge with supporting blocks, welded seam at the front of the wedge. It would be heavy, but rock solid.

Why does no one use Stainless Steel? It weighs the same, can't see a noticeable difference in price?

The 2mm stuff I had on BitzaWood stood up pretty well. LH's punch axe head put holes in it, but everything else just scuffed it. It was only really 360 that put it massively out of shape, and even blew holes in it! But we all know what 360 can do.

The 2mm on the back of Kaizer stood up to Boner, so it could be used, the weight is about a 5% difference which could make the difference to the grams (2008 champs, the weight Marco had to cut out of Trojan was rediculous).

I believe stainless Steel is a pain in the a$$ machine and weld. I also thought it was more expensive which I imagine gets more substantial when you go to thicker sheets. But saying that its probably easier than hardox!
But I think people use it for drums on drum spinners- I know that I did and so did drumroll.

Yeh I found it harder to drill than Ti!

As did I. Mind you I did have to drill 10mm stainless but only 2mm Ti

I also had a lot of trouble drilling it too, blunted a couple of drill bits in the process.

I found hardox ridiculous to drill when I used it once. Only managed to make 3 holes.

Been a rather productive night
I have mounted the motors, tapped a few dozen holes and popped everything in to see how its all looking.

Few pictures with most of the components in and the wheels placed to see how it looks.
Attachment 3793Attachment 3794Attachment 3795

Wotty is very tight and resting on the motors. I have created a new wanted thread to see if any one has a sidewinder lying around as thats the most suitable ESC for this. (or possible a victor)
Attachment 3796
If no one has a second hand one then I should use the wotty as I have no plans for it in anything else for bare minimum a year. I will only save about 500 grams going with a sidewinder. If I stick to the wotty then I will tweak the chassis a bit. Not a giant issue. Just move everything back 6mm and that will stop the watty resting on it.

Decided I am going to go with 3.5:1 reduction for now. As mentioned I have the options to change it but I could do with just seeing how it drives with the added voltage.

Also decided to just purchase some new lipos now. I was originally going to wait for the second version (with the weapon) But I might as well make the upgrade now and it will save about 1kg from the existing nicads. Plus a ton of space and higher discharge rates.
Not sure to go for 2, 4cell (29.6v) or 3, 3 cell (33.3volts)
Will do some calculations I have some time before I need to make a decision

Talking about batteries. I harvested an old laptop battery and made a pack out of it. Done a bit of homework and found these to be Li-ion batteries and have about half the current draw that a li-po has. Also these are rather old (8 year old laptop). But it could be used in a kilobot or something.

Attachment 3797

Main jobs now is the transmission. Have 1 wheel done. Need to make 3 more.

*EDIT*
I would also like to use this opportunity to thank everyone so far for making me feel really welcomed again. I didn't just stop building things when I took a break from this hobby. I built a few arcade systems and handheld game units and the forums and community felt very dry and unwelcoming. Getting any kind of feedback was like getting blood from stone. Keep being awesome and looking forward to my next event.

I would suggest you go 6S Li-Po and use those Turnigy TZ85 ESCs. That would be the smallest, lightest, cheapest and most robust option.
There are currently some issues with mixing though when using OrangeRxs which I believe are being resolved as we speak.

Not sure how happy the 85s would be right at both their voltage and amperage limit.

They'd run that no problem- looking great btw Godzilla, good to see you back :D

Good to hear from you Mouldy :) Knew it wouldn't be long to be called Godzilla :P

Yeah I picked up two 85as from Aussie land. Not sure when I will expect them but probably 2 weeks. If they work fine and with the lipo that means I have saved probably 2kg. Crazy. So I need to start thinking about the weapon.

This weekend has been spent most on the transmission. Its been really tricky at times, especially without a lathe. But I have had good success.
Important that the gears are aligned but the wheels have a bit of travel (MM or two).

I managed to mount the 16 tooth fine onto the motor. Quite surprised as this was my third attempt. Two years ago I seemed to have some trouble.
Attachment 3805Attachment 3806
Sadly have quite a big job ahead of me. I originally planned to mount roller bearings into the wheels but have instead decided to mount them into the chassis. So I need to take off all the snap on parts on the bulkheads and bore out the wheel shafts properly.

I also have to create a new motor mount. After the weight reduction its not solid enough. So I have some spare 14mm nylon and will make a new one.

Here is a video of testing the first stage of the drive.
Attachment 3807

https://www.youtube.com/watch?v=kdvYAcv6ncA&list=UU8wdYybWk4a32cGdtUiP YgQ& index=1

How did you mount the gear on the Scooter motor shaft? Grubs screws and a flat on the shaft?

Already drilled a 4mm hole in the motor shaft a so I just drilled through the spur gear popped a bolt through with a m4 nylon nut.

How big is the shaft!?